I am making peanut brittle with an old parent's recipe. The recipe calls for boiling the "syrup" ingredients to 250 degrees, then add peanuts, butter, stir to cook peanuts for 10 minutes and then pour onto porcelain table and spread. Problem is that I'm cooking in Denver, recipe was perfected at 800 feet elevation. The brittle is coming out like bad fudge, crumbly, and not at all the "hard crack" that the thermometer indicates. Ideas?

Welcome to DC. I have sent other friends to this site that will help with all kinds of higher elevation cooking, including candymaking. Good luck. This article explains the formula and adjustments that you must make:Mile-high candy making requires adjustments

You can google search high elevation baking and candymaking for more information.